It looks like something someone created with a spirograph, but it's called a connectogram, and it's increasingly being used by neuroscientists to map and interpret the complex connections of white matter fiber buried deep inside the human brain.

The graphs are compiled through the use of diffusion weighted (DWI) and magnetic resonance imaging (MRI). Using these tools, neuroscientists can assess white matter fiber pathways between brain regions to measure fiber bundle properties, as well as their influence on behavior and cognition.

The connectogram shown above represents the inter-brain-region connections of 110 right-handed men. The left side of the circle represents the left hemisphere, and the right side the right hemisphere.

Within each lobe, each cortical area is assigned an abbreviation and a unique color. The color codes themselves represent the strength of the connections (including fractional anistropy, or white matter integrity). Image credit: John Darrell Van Horn.